Issue #649: Wrong days remaining label when submitting a new proposal

app/views/proposal/_encouragement_text.html.haml

@@ -6,18 +6,18 @@
     Proposals should fit in one of the
     = "#{pluralize(@conference.tracks.count, 'track')}:"
     = "#{tracks(@conference)}."
-  - if @conference.call_for_paper
+  - if @conference.cfp_open?
     The submission period has begun
     %em
       = @conference.call_for_paper.start_date.strftime('%A, %B %-d. %Y')
     and closes
     %em
       = @conference.call_for_paper.end_date.strftime('%A, %B %-d. %Y.')
-    That means you have only
-    - days = (@conference.call_for_paper.end_date - Date.today).to_i
-    %b
-      = pluralize(days, 'days')
-      left!
-  Remember
-  = @conference.title
-  will only be as good as the content you present. Submit early, submit often!
+    That means you have
+    %b= pluralize(@conference.call_for_paper.remaining_days, 'day')
+    left!
+    Remember
+    = @conference.title
+    will only be as good as the content you present. Submit early, submit often!
+  -else
+    The submission period is closed now.